The present invention relates to ink containers for providing ink to inkjet printers. More specifically, the present invention relates to a method and apparatus for refilling a replaceable ink container having a capillary storage member for retaining and providing the controlled release of ink from the ink container.
Inkjet printers frequently make use of an inkjet printhead mounted within a carriage that is moved back and forth across print media, such as paper. As the printhead is moved across the print media, a control system activates the printhead to deposit or eject ink droplets onto the print media to form images and text. Ink is provided to the printhead by a supply of ink that is either carried by the carriage or mounted to the printing system not to move with the carriage.
For the case where the ink supply is not carried with the carriage, the ink supply can be in continuous fluid communication with the printhead by the use of a conduit to replenish the printhead continuously. Alternatively, the printhead can be intermittently connected with the ink supply by positioning the printhead proximate to a filling station that facilitates connection of the printhead to the ink supply.
For the case where the ink supply is carried with the carriage, ink supply may be integral with the printhead, whereupon the entire printhead and ink supply is replaced when ink is exhausted. Alternatively, the ink supply can be carried with the carriage and be separately replaceable from the printhead. For the case where the ink supply is separately replaceable, the ink supply is replaced when exhausted, and the printhead is replaced at the end of printhead life. Regardless of where the ink supply is located within the printing system, it is critical that the ink supply provides a reliable supply of ink to the inkjet printhead.
In addition to providing ink to the inkjet printhead, the ink supply frequently provides additional functions within the printing system, such as maintaining a negative gauge pressure, frequently referred to as a back pressure, within the ink supply and inkjet printhead. Gauge pressure a pressure within the inkjet printhead relative to an atmospheric pressure. This negative gauge pressure must be sufficient so that a head pressure associated with the ink supply is kept at a value that is lower than the atmospheric pressure to prevent leakage of ink from either the ink supply or the inkjet printhead frequently referred to as drooling. The ink supply is required to provide a negative gauge pressure or back pressure over a wide range of temperatures and atmospheric pressures in which the inkjet printer experiences in storage and operation.
There is an ever-present need for ink containers for supplying ink to the inkjet printhead in a reliable manner. These ink containers should provide sufficient back pressure to prevent ink leakage during normal handling and temperature and pressure variations the ink container experiences during normal use and storage. In addition, these ink containers should have relatively low manufacturing costs to reduce the per page printing costs.
One aspect of the present invention is an apparatus for refilling a replaceable ink container. The ink container has a top and bottom portion relative to a gravitational frame of reference. The replaceable ink container further has a capillary storage member disposed therein and a fluid outlet disposed on the bottom portion. The apparatus for refilling includes a fluid interconnect configured for insertion into the bottom portion to compress the capillary storage member. Included is means for determining an amount of ink to fill the replaceable ink container. Also included is an ink delivery device for providing the determined quantity of ink to the replaceable ink container through the fluid interconnect. The ink delivery device is configured to deliver ink to the ink container positioned in a bottom down orientation relative to the gravitational frame of reference to provide ink to the capillary storage member proximate the fluid outlet.
In one preferred embodiment the means for determining an amount of ink is a back pressure measuring device for measuring back pressure tending to draw ink toward the capillary storage material.